1. Field of the Invention
The present invention relates to a training instrument. More specifically, the present invention relates to a training instrument in order to make stronger muscles including inner muscle of the arm, shoulder and the like of sportsman.
2. Description of the Related Art
In the related art, a training instrument for improving a golfer's golf swing is disclosed in Japanese Laid-open Patent Publication No. 2005-270275.
The training instrument is formed using a sheet of film flexible enough to wrap cylindrically around a shaft of a commercial golf club.
Four wings are attached to the film at fixed positions so that they can radially spread around the shaft of a commercial golf club.
However, the above training instrument lacks practical use.
When strongly swinging the training instrument for training, a very big air resistance with which the wings are met makes the cylindrical film distort and prevents it from rotating smoothly around the shaft of the golf club.